The ETI microwave was not our style as well.
Here is an inexpensive lightweight microwave that fits the hole. Keep in mind that the door will not close over it due to the handle...but I wanted the door to use elsewhere.

I used some perforated metal strip that can be purchased at any hardware store to secure it to the cabinet. The strips are attached on the underside of the microwave where the two front feet were. I had to remove the microwave cover to property secure the straps to where the feet were. Please make sure that the microwave is unplugged if you remove the cover and that you donít touch any internal parts as they could still be holding a deadly charge. If you are uncomfortable with removing the top I am sure you can attach the metal strap to the underside with very long strips of double sided foam tape. Just make sure you wipe any oil film off the microwave and strip. I also added some pool noodle blocks on the top at the rear to keep it from bouncing should it decide to do so.

We replaced our microwave with a .7 cu in RCA with dimensions of 18 x 10 x 12.75. Not sure the dimensions of the 19 are the same. We installed with the same aluminum "L" stock used by Escape (see their website), Epoxied to the outside of the microwave and screwed into the face of cabinet. Be advised that there is torque on this setup if you are driving over rough roads. When you go over a bump, the rear of the microwave, where most of the mass is, is forced upwards placing torque force on the fasteners. We have compensated for this by glueing supports ON THE BACK of the microwave extending up to the ceiling of the cabinet and preventing any upward movement of the microwave while going over bumps.

For our 2017 19', after much searching, we settled on a 0.7 cu. inch Mainstays microwave from Walmart (19.53 x 13.94 x 11.50). The build quality appears questionable but the size was right. It fits the space easily top-to-bottom and sides. Depthwise it just makes it, not quite flush with the cabinet front. The biggest fit problem is from the microwave's rear plug. It prevents the microwave from being pushed all the way back into the cabinet. We solved that by using a 12" extension cord with flat rotating plug from Amazon. Like you we won't bring the microwave on boondocking trips. We wanted easy in easy out capability. To achieve that we plan to hold it in place for transit using a strapping system. One strap end will terminate inside the wardrobe on the right side of the fridge. The other end will terminate on the wall on the bed side of the fridge. The strap, naturally, will go in front of the microwave while in transit. I found a YYST 54" battery tie hold down strap kit on Amazon that should work. We'll see.

We replaced our microwave with a .7 cu in RCA with dimensions of 18 x 10 x 12.75. Not sure the dimensions of the 19 are the same. We installed with the same aluminum "L" stock used by Escape (see their website), Epoxied to the outside of the microwave and screwed into the face of cabinet. Be advised that there is torque on this setup if you are driving over rough roads. When you go over a bump, the rear of the microwave, where most of the mass is, is forced upwards placing torque force on the fasteners. We have compensated for this by glueing supports ON THE BACK of the microwave extending up to the ceiling of the cabinet and preventing any upward movement of the microwave while going over bumps.

I took 4 pieces of pool noodle that were cut to size and placed them to the back of the microwave. Two on the very top and two for the bottom. May never have loosened anyway but it for sure will not now.

I took 4 pieces of pool noodle that were cut to size and placed them to the back of the microwave. Two on the very top and two for the bottom. May never have loosened anyway but it for sure will not now.

I worry this strategy will diminish already minimal air circulation available in the cabinet.